Put extra electrons in charged system around molecular center rather than on top of one and another

git-svn-id: https://subversion.assembla.com/svn/qmcdev/trunk@5708 e5b18d87-469d-4833-9cc0-8cdfa06e9491

src/QMCApp/InitMolecularSystem.cpp

@@ -121,7 +121,10 @@ namespace qmcplusplus {
     vector<LoneElectron> loneQ;
 
     double rmin=cutoff; 
+
+    ParticleSet::SingleParticlePos_t cm;
     for(int iat=0; iat<Centers; iat++) { 
+      cm += ions->R[iat];
       for(int nn=d_ii->M[iat]; nn<d_ii->M[iat+1]; nn++){
         rmin = std::min(rmin,d_ii->r(nn));
       }
@@ -148,6 +151,29 @@ namespace qmcplusplus {
       ++it;
     }
 
+    //extra electrons around the geometric center
+    double cnorm=1.0/static_cast<double>(Centers);
+    cm=cnorm*cm;
+    if(nup_tot<numUp)
+    {
+      double sep=rmin*2;
+      int iu=0;
+      while(nup_tot<numUp)
+      {
+        els->R[nup_tot++]=cm+sep*chi[iu++];
+      }
+    }
+
+    if(ndown_tot<numDown)
+    {
+      double sep=rmin*2;
+      int iu=0;
+      while(ndown_tot<numDown)
+      {
+        els->R[ndown_tot++]=cm+sep*chi[iu++];
+      }
+    }
+
     //put all the electrons in a unit box
     if(els->Lattice.SuperCellEnum != SUPERCELL_OPEN) 
     {